Electronic device with charging-coil independent rear-facing antenna
An electronic device may have conductive sidewalls and a rear wall. The rear wall may have a first portion mounted to the sidewalls and a second portion protruding away from the first portion to define a cavity. A sensor board may be mounted within the cavity. A coil structure may be mounted within the cavity and surrounding the sensor board. An antenna may have an antenna ground separated from a patch element by an antenna volume. The patch element may include a first conductive trace on the first portion of the rear wall, a second conductive trace on the sensor board, and a conductive interconnect structure that couples the first conductive trace to the second conductive trace. The coil structure may be disposed outside of the antenna to minimize impact of the coil structure on performance of the antenna.
1 . An electronic device comprising:
a display;
a housing wall opposite the display;
a first conductive trace patterned on a surface of the housing wall;
a sensor board having a first surface facing the display and a second surface opposite the first surface and facing the housing wall;
a second conductive trace patterned on the first surface of the sensor board; and
an antenna having an antenna ground and having an antenna resonating element configured to radiate through the housing wall, wherein the antenna resonating element comprises the first conductive trace patterned on the surface of the housing wall and the second conductive trace patterned on the first surface of the sensor board.
2 . The electronic device of claim 1 , wherein the antenna resonating element further comprises a conductive interconnect that couples the first conductive trace to the second conductive trace.
3 . The electronic device of claim 2 , further comprising a positive antenna feed terminal coupled to the first conductive trace.
4 . The electronic device of claim 1 , wherein the housing wall has a first dielectric portion and a second dielectric portion that protrudes away from the first dielectric portion to define a cavity, the sensor board being disposed at least partially within the cavity.
5 . The electronic device of claim 4 , further comprising:
a coil disposed extending around the sensor board, wherein the coil is different from the antenna; and
wireless power receiver circuitry configured to receive wireless charging signals using the coil.
6 . The electronic device of claim 5 , wherein the antenna resonating element and the antenna ground define a volume of the antenna, the coil being disposed within the cavity and outside the volume of the antenna.
7 . The electronic device of claim 1 , wherein the electronic device has a central axis that extends through the second conductive trace, the first conductive trace following a loop path that extends laterally around the central axis.
8 . The electronic device of claim 1 , wherein the sensor board comprises an optical sensor configured to transmit and receive light through the housing wall.
9 . The electronic device of claim 1 , wherein the first conductive trace and the second conductive trace are configured to resonate in a frequency band greater than or equal to 600 MHz.
10 . The electronic device of claim 9 , further comprising:
a coil configured to receive wireless power through the rear housing wall at a frequency less than 100 MHz, wherein the coil is different than the antenna resonating element, the coil laterally surrounds the sensor board and a central axis, and conductive material in the coil at least partially overlaps the first conductive trace as viewed along a normal axis of the display.
11 . An electronic device comprising:
a display;
a housing having a dielectric housing wall opposite the display, the dielectric housing wall having a protrusion that defines a cavity;
a printed circuit board disposed at least partially within the cavity, wherein the printed circuit board has a first surface facing the display and a second surface opposite the first surface and facing the dielectric housing wall; and
an antenna having a patch element, an antenna ground, and a positive antenna feed terminal coupled to the patch element, wherein the patch element includes a first conductive trace patterned on a surface of the dielectric housing wall, a second conductive trace patterned on the first surface of the printed circuit, and a conductive interconnect that couples the first conductive trace to the second conductive trace.
12 . The electronic device of claim 11 , further comprising:
a coil that is different from the antenna and that is disposed within the cavity and extending around the printed circuit board; and
wireless power receiver circuitry configured to receive wireless charging signals using the coil.
13 . The electronic device of claim 12 , wherein the patch element is separated from the antenna ground by a volume of the antenna, the coil being disposed external to the volume of the antenna.
14 . The electronic device of claim 11 , further comprising a sensor mounted to the second surface of the printed circuit board.
15 . The electronic device of claim 11 , wherein the first conductive trace has an inner edge, the second conductive trace has an outer edge, and the conductive interconnect couples the inner edge of the first conductive trace to the outer edge of the second conductive trace.
16 . The electronic device of claim 15 , wherein the conductive interconnect comprises a bent piece of metal.
17 . The electronic device of claim 15 , wherein the inner edge overlaps the second conductive trace as viewed along a normal axis of the display.
18 . The electronic device of claim 11 , wherein the first conductive trace and the second conductive trace are configured to convey an antenna current at a frequency greater than or equal to 600 MHz, the conductive interconnect being configured to pass the antenna current between the first and second conductive traces.
19 . A wristwatch comprising:
conductive sidewalls;
a display mounted to the conductive sidewalls;
a dielectric wall opposite the display, wherein the dielectric wall has a first portion mounted to the conductive sidewalls and has a second portion that protrudes from the first portion and that defines a cavity;
a circuit board in the cavity;
a coil in the cavity and extending around the circuit board;
a first conductive trace on the circuit board;
a second conductive trace on the first portion of the dielectric wall;
a conductive interconnect that couples the first conductive trace to the second conductive trace, wherein the conductive interconnect comprises a piece of metal that has a first end coupled to the second conductive trace, a second end opposite the first end, and a bend between the first end and the second end, the second end is bent towards the display, and the bend contacts the first conductive trace; and
an antenna having a radiating element that includes the first conductive trace, the second conductive trace, and the conductive interconnect.
20 . The wristwatch of claim 19 , further comprising a sensor on the circuit board, wherein the antenna has a positive antenna feed terminal coupled to the first conductive trace and the conductive interconnect comprises a conductive bracket.